Desert Runners

There is something called the "4 Deserts Grand Slam". It's relatively straightforward - to qualify participants have a single calendar year to run four ultramarathons, one in each of four deserts. The Atacama, the Gobi, the Sahara and Antarctica.

That's "ultramarathon" in the "bigger than a marathon" sense - not 26 miles, no - just under six times that, 155. One hundred and fifty five miles, across a desert and again another three times, in a year. One thousand kilometers in total, one million metres. That's the distance between London and Copenhagen, between Pyongyang and Osaka. It's a long way. If you're heading to Tipperary, your long way starts in Maastricht.

Similarly international are the runners aiming for the Grand Slam. Among them are Americans, Australians, Britons, and Dave. Dave's from Ireland, and he's one of the main reasons there's a movie - Director Jennifer Steinman heard him talking about his plan to try the 4 Deserts Grand Slam at a conference, and then asked if she could film him. It's not an easy process - indeed, the suffering and anguish we're shown over the course of the four races isn't to be trivialised, and blisters that truly deserve a gore warning aren't the half of it.

All of the athletes have their own reasons to be running, and while they've got their own things to push them again and again, it's as companions that they sustain each other. It's a neat trick of human nature that people can build friendships, communities, even amid the loneliness of the long-distance runner. The film follows them across the deserts, and at home in between, and then across the deserts, and then at home in between. It's not an easy process.

Dean Karnazes is credited as executive producer, a role he qualifies for as an ultramarathon legend. He achieved his Grand Slam in 2008, the first year that anyone managed it. Desert Runners follows 14 people attempting to replicate his feat.

There's geographic variation: these are the driest, windiest, hottest, coldest deserts on earth; there's about 75 degrees centigrade of temperature variation across the races; the landscapes are surreal, astonishing. "This is what I imagine Hell to be like", we're told. "It's like death."

It's inescapable. There's grief, rage, even violence, death - and running. Always running. Some running from, some running to, some running with, some running away. The physical challenge is significant, and in somewhat the same direction the sheer process of creating this film. In the same way that the Warner Brothers logo that says "An AOL Time Warner Company" dates a film like the sedimentary layers or strata that the Grand Slammers pass through, Desert Runners is in part a product of the modern crowd-funding era - Kickstarter backers are thanked in the credits, part of the long process of getting this film into cinemas. The Grand Slam attempts were made in 2010, but Desert Runners is worth the wait.

There are two basic rules to documentary: find something interesting, show it in an interesting way. With the help of Andy Cooper's animated on-screen graphics, Sevan Matossian's camera work that sometimes borrows time-lapse from the toy-cupboard to good effect, and Eric Holland's score, Jennifer Steinman has achieved something special. It feels trite to say that it's well-paced, that you should run to see it, but let's - the 4 Deserts Grand Slam is evidently life-changing, and the feats of the Desert Runners are certainly awe-inspiring.